rev=true in searchsorted_interval (#111)

* rev=true in searchsorted_interval

Co-authored-by: hyrodium <hyrodium@gmail.com>

* add zero-step range tests

* use searchsorted(lt=<)

---------

Co-authored-by: hyrodium <hyrodium@gmail.com>

Author: aplavin

src/findall.jl

@@ -34,45 +34,8 @@ julia> findall(in(Interval{:open,:closed}(1,6)), y) # (1,6], does not include 1
 5:14
 ```
 """
-function Base.findall(interval_d::Base.Fix2{typeof(in),Interval{L,R,T}}, x::AbstractRange)  where {L,R,T}
-    isempty(x) && return 1:0
-
-    interval = interval_d.x
-    il, ir = firstindex(x), lastindex(x)
-    δx = step(x)
-    a,b = if δx < zero(δx)
-        rev = findall(in(interval), reverse(x))
-        isempty(rev) && return rev
-
-        a = (il+ir)-last(rev)
-        b = (il+ir)-first(rev)
-
-        a,b
-    else
-        lx, rx = first(x), last(x)
-        l = max(leftendpoint(interval), lx - oneunit(δx))
-        r = min(rightendpoint(interval), rx + oneunit(δx))
-
-        (l > rx || r < lx) && return 1:0
-
-        a = il + max(0, round(Int, cld(l-lx, δx)))
-        a += (a ≤ ir && (x[a] == l && L == :open || x[a] < l))
-
-        b = min(ir, round(Int, cld(r-lx, δx)) + il)
-        b -= (b ≥ il && (x[b] == r && R == :open || x[b] > r))
-
-        a,b
-    end
-    # Reversing a range could change sign of values close to zero (cf
-    # sign of the smallest element in x and reverse(x), where x =
-    # range(BigFloat(-0.5),stop=BigFloat(1.0),length=10)), or more
-    # generally push elements in or out of the interval (as can cld),
-    # so we need to check once again.
-    a += +(a < ir && x[a] ∉ interval) - (il < a && x[a-1] ∈ interval)
-    b += -(il < b && x[b] ∉ interval) + (b < ir && x[b+1] ∈ interval)
-
-    a:b
-end
+Base.findall(interval_d::Base.Fix2{typeof(in), <:Interval}, x::AbstractRange) =
+    searchsorted_interval(x, interval_d.x; rev=step(x) < zero(step(x)))
 
 # We overload Base._findin to avoid an ambiguity that arises with
 # Base.findall(interval_d::Base.Fix2{typeof(in),Interval{L,R,T}}, x::AbstractArray)
@@ -85,7 +48,7 @@ function Base._findin(a::Union{AbstractArray, Tuple}, b::Interval)
 end
 
 """
-    searchsorted_interval(a, i::Interval)
+    searchsorted_interval(a, i::Interval; [rev=false])
 
 Return the range of indices of `a` which is inside of the interval `i` (using binary search), assuming that
 `a` is already sorted. Return an empty range located at the insertion point if a does not contain values in `i`.
@@ -102,9 +65,15 @@ julia> searchsorted_interval(Float64[], 1..3)
 1:0
 ```
 """
-function searchsorted_interval end
+function searchsorted_interval(X, i::Interval{L, R}; rev=false) where {L, R}
+    if rev === true
+        _searchsorted_begin(X, rightendpoint(i), Val(R); rev):_searchsorted_end(X, leftendpoint(i), Val(L); rev)
+    else
+        _searchsorted_begin(X, leftendpoint(i), Val(L); rev):_searchsorted_end(X, rightendpoint(i), Val(R); rev)
+    end
+end
 
-searchsorted_interval(X, i::Interval{:closed, :closed}) = searchsortedfirst(X, leftendpoint(i))     :searchsortedlast(X, rightendpoint(i))
-searchsorted_interval(X, i::Interval{:closed,   :open}) = searchsortedfirst(X, leftendpoint(i))     :(searchsortedfirst(X, rightendpoint(i)) - 1)
-searchsorted_interval(X, i::Interval{  :open, :closed}) = (searchsortedlast(X, leftendpoint(i)) + 1):searchsortedlast(X, rightendpoint(i))
-searchsorted_interval(X, i::Interval{  :open,   :open}) = (searchsortedlast(X, leftendpoint(i)) + 1):(searchsortedfirst(X, rightendpoint(i)) - 1)
+_searchsorted_begin(X, x, ::Val{:closed}; rev) = searchsortedfirst(X, x; rev, lt=<)
+_searchsorted_begin(X, x,   ::Val{:open}; rev) =  searchsortedlast(X, x; rev, lt=<) + 1
+  _searchsorted_end(X, x, ::Val{:closed}; rev) =  searchsortedlast(X, x; rev, lt=<)
+  _searchsorted_end(X, x,   ::Val{:open}; rev) = searchsortedfirst(X, x; rev, lt=<) - 1

test/findall.jl

@@ -150,6 +150,12 @@ end
         end
     end
 
+    @testset "zero-step ranges" begin
+        r = range(1, 1, length=10)
+        @test findall(in(1..3),r) == 1:10
+        @test findall(in(2..3),r) |> isempty
+    end
+
     @testset "searchsorted" begin
         x = [-10, 0, 1, 1 + eps(), 1.2, 1.5, 1.9, 2 - eps(), 2]
         @test searchsorted_interval(x, -Inf..Inf) == 1:9